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    991 Turbo S Boost Pressure???

    Hi guys.

    I need to ask you a favor: If you already own a 991 Turbo S or if you are in the process of driving one soon, would you please pay attention to the maximum boost pressure? The car needs to be in Sport or Sport Plus mode.

    Porsche claims that the 991 Turbo S delivers 1.2 bar boost pressure with an additional 0.15 bar overboost on top for about 20 seconds (full acceleration with "kickdown").

    However: I have never seen more than 1.2 bar boost pressure on my car's digital boost readout, not even with overboost.

    So what is going on here? I try to find out next week but until then, please do me the favor to pay attention to your maximum boost pressure, no matter if it is your own car or a car from the dealer.

    Nothing to be alarmed of, I'm just curious.

    Thank you!


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


    Re: 991 Turbo S Boost Pressure???

    i don't own the car, but my understanding the normal boost is 1.0 bar and when you fully depressed the accelerator in sport or sport plus mode you get the additional (overboost) of 0.15


    Re: 991 Turbo S Boost Pressure???

    By the way, did you tried to fully depress the accelerator in the normal mood and the read the maximum boost pressure?

    if you didn't get over 1.0 then i stand correct with my earlier post.


    Re: 991 Turbo S Boost Pressure???

    If it is like mine (old 997.1 turbo), you must depress the gas QUICKLY to the floor.  It works for me, even in 1st.

    Do you see an up arrow or any other overboost indicator showing the overboost is active?

     


    Re: 991 Turbo S Boost Pressure???

    orsi2003:

    i don't own the car, but my understanding the normal boost is 1.0 bar and when you fully depressed the accelerator in sport or sport plus mode you get the additional (overboost) of 0.15

    Normal maximum boost pressure is 1.2 bar plus 0.15 bar overboost.

    This is why I asked owners or those who are driving one nowSmiley


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


    Re: 991 Turbo S Boost Pressure???

    Leawood911:

    If it is like mine (old 997.1 turbo), you must depress the gas QUICKLY to the floor.  It works for me, even in 1st.

    Do you see an up arrow or any other overboost indicator showing the overboost is active?

     

    Maximum boost pressure usually shows up when you put the car in a higher gear (like the 6th for example) at low speeds and fully press the throttle down instantly.

    It confuses me that some people (incl. myself) see 1.2 bar only at max. but others claim they see 1.35 bar (which is kind of weird because the boost pressure gauge isn't supposed to show a second digit after the . (it should show 1.3 or 1.4 bar but not 1.35 bar).

    My suspicion is that the boost pressure gauge shows the normal maximum boost pressure of 1.2 bar but not the overboost pressure. Overboost is shown only by the orange digits of the boost pressure. Still no confirmation about that.


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


    Re: 991 Turbo S Boost Pressure???

    Maybe there is a limit to the boost pressure for the first 5000km? I remember when I tested a 997 Mk-II the launch control would not rev to the max revs, it only went up to 4000 I believe because the car had less than 5k on it, I don't remember if the 991 was the same when I drove it. Just guessing but maybe there is a similar mechanism with the boost pressure in the 991TTS?


    --


    Re: 991 Turbo S Boost Pressure???

    there is nothing like a 'built in' break-in mode.

    the same was said about the 997 Turbo when it first came out, that overboost will only kick in after the break-in period. not true, there is no break in Feature built into the ECU.

    while i certainly dont question your experience with your car, i have not heard of any 997 MK-II that would not rev above 4000 earlier than 5k kilometres.

    i did not own a mk-II, but drove a friend's when it was still new at about 1500 km's and it surely revved all the way to the redline.

    as RC correctly stated, overboost kicks in the longest, when accelerating from low Speed in high gears and keeping the pedal down. however, boost pressure is influenced highly by fuel Quality and ambient temperature and Elevation.


    --
    Speed has never killed anyone, suddenly becoming stationary... That's what gets you.

    Re: 991 Turbo S Boost Pressure???

    sorry, just reread your post and see that you are referring to Launch control.

    with Launch control, the engine does not rev up to the max rpm. it revs up to the Point where it starts off with the highest torque/hp Ratio. that usually would sit at 4-5k rpm.

    in my GT2 Launch control goes to about 4800 rpm IIRC.


    --
    Speed has never killed anyone, suddenly becoming stationary... That's what gets you.

    Re: 991 Turbo S Boost Pressure???

    Thanks guys. I now have an answer to my own question.

    A little background why I asked: On a German Porsche forum, someone claimed he saw 1.35  bar on the gauge most of the time, which is impossible since I know now that the gauge doesn't even show the overboost pressure and no second digit after the . (so no 1.35 but only 1.3 for example).

    Now here is the thing: The gauge shows 1.2 bar maximum boost pressure only, the overboost is only displayed as an orange coloring of the digits but not in digits (which is kind of weird but this is how it is). So that guy clearly lied.

    In the lower speed range, boost pressure is usually around 0.8 to 1.0 bar (always full throttle and Sport mode active), for short periods up to 1.1 bar. I usually see 1.2 bar at speeds over 240 kph only.

    Since my car seems to run pretty well (I mentioned the Performance Box measurements in the "owner" thread), I don't think there are any issues with boost pressure. This is how it is supposed to be.

    Regarding a "built-in" break-in mode: Actually, there is one. I don't know if Porsche uses it but BMW M for example uses it. This is why the speed limit raise (optional for M cars) is only active after the break-in period.  I also heard that some other manufacturers are using such a break-in mode too but I have no proof for it.


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


    Re: 991 Turbo S Boost Pressure???

    RC, i have the delimited Speed on my X6M and I was driving 270 km/h before the recommended break-in period was reached.

    I recall having had this discussion before and I had checked with my dealer who confirmed that there was no such thing.

    Maybe it is market dependant....


    --
    Speed has never killed anyone, suddenly becoming stationary... That's what gets you.

    Re: 991 Turbo S Boost Pressure???

    intouch1:

    RC, i have the delimited Speed on my X6M and I was driving 270 km/h before the recommended break-in period was reached.

    I recall having had this discussion before and I had checked with my dealer who confirmed that there was no such thing.

    Maybe it is market dependant....

    Could be. Neither our M3 Cab nor our X5M was "delimited" within the first 2000 km. After 2000 km, the 250 kph limit was suddenly gone. With the M3 Cab, the dealer actually told me that I need to come to the dealership and have the 280 kph limit "activated" but when I brought my car, the mechanic told me that it activates itself after 2000 km and he was right, there was no need for any activation. Fun part: I was on the Autobahn, driving 260 kph on the speedo (more wasn't possible) and passed to 2000 km being on the Autobahn and still, I wasn't able to drive faster. When I stopped at a parking lot, stopped the engine and restarted it after five minutes (had to pee...), the limit was gone. Smiley So there seems to be some sort of switch in the software which correlates to the mileage. So I wouldn't exclude it that some manufacturers actually limit the boost pressure (or even rev figure) for the first couple of miles (500, 1000 or whatever) to protect the engine/drivetrain from damage. Just a guess though, I've never read an official statement about such a thing.


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


    Re: 991 Turbo S Boost Pressure???

    RC:

     I also heard that some other manufacturers are using such a break-in mode too but I have no proof for it.

    I recently learned that Chryslers SRT 6.4 HEMI has a break in mode. Reduced power and no launch control for the first 500 miles! Smiley

     


    Re: 991 Turbo S Boost Pressure???

    Lars997:
    RC:

     I also heard that some other manufacturers are using such a break-in mode too but I have no proof for it.

    I recently learned that Chryslers SRT 6.4 HEMI has a break in mode. Reduced power and no launch control for the first 500 miles! Smiley

     

    Learned something new again...thanks.  Smiley

    Btw: Photos please. Smiley


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


    Re: 991 Turbo S Boost Pressure???

    RC:

    Thanks guys. I now have an answer to my own question.

    A little background why I asked: On a German Porsche forum, someone claimed he saw 1.35  bar on the gauge most of the time, which is impossible since I know now that the gauge doesn't even show the overboost pressure and no second digit after the . (so no 1.35 but only 1.3 for example).

    Now here is the thing: The gauge shows 1.2 bar maximum boost pressure only, the overboost is only displayed as an orange coloring of the digits but not in digits (which is kind of weird but this is how it is). So that guy clearly lied.

    In the lower speed range, boost pressure is usually around 0.8 to 1.0 bar (always full throttle and Sport mode active), for short periods up to 1.1 bar. I usually see 1.2 bar at speeds over 240 kph only.

    Since my car seems to run pretty well (I mentioned the Performance Box measurements in the "owner" thread), I don't think there are any issues with boost pressure. This is how it is supposed to be.

    Regarding a "built-in" break-in mode: Actually, there is one. I don't know if Porsche uses it but BMW M for example uses it. This is why the speed limit raise (optional for M cars) is only active after the break-in period.  I also heard that some other manufacturers are using such a break-in mode too but I have no proof for it.

    sounds like they are using the same setup as the 997 TT. the boost gauge on the 997 could not read more than 1.2 even if the car was modified to 1.3 or 1.4. my old car was modded and i only saw 1.2 max, tuner found out that gauge reading was limited to 1.2. 


    --

    2011 CTT, 2013 12C Spider, 2013 A5 cab, 2014 4Runner Trail Edition

     

     


    Re: 991 Turbo S Boost Pressure???

    Lars997:
    RC:

     I also heard that some other manufacturers are using such a break-in mode too but I have no proof for it.

    I recently learned that Chryslers SRT 6.4 HEMI has a break in mode. Reduced power and no launch control for the first 500 miles! Smiley

     

    I also have a new 14 Jeep SRT and yes the launch control works perfectly from day one. 

    I do know that the corvette stingray does have a digital "break in tach" which reverts to a normal tach when 500 miles is reached. 


    Re: 991 Turbo S Boost Pressure???

    The Jeep SRT Lars ordered is the European version, so maybe a couple of things are different. 


    --

    RC (Germany) - Rennteam Editor Porsche 991 Turbo S, Cayenne GTS (958), BMW X3 35d (2013)


     
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